Acquisition of information from rapidly presented verbal and nonverbal stimuli

Two experiments tested recognition memory for rapidly presented stimuli. In Experiment I 16 words were presented at exposure times ranging from 25 to 500 msec followed by a yes-no recognition test. The results showed a strong dependence of memory performance on both exposure time and serial position. In Experiment II 16 random forms were presented at exposure times ranging from 125 to 2000 msec followed by a yes-no recognition test. Results for random forms showed that memory performance was strongly dependent on exposure time but not on serial position. Taken together, the results of Experiments I and II suggest qualitative encoding differences between verbal vs nonverbal stimuli.     

Semantic memory: Searching for attributes vs searching for names

The purpose of this experiment was to determine whether searching for a word that has a particular attribute (a fruit that is yellow) involves a different process than searching for a word whose name has a particular form (a fruit whose name begins with "p"). Ss saw category nouns paired with adjectives or letter restrictors presented on a series of blocked trials and a series of mixed trials. The Ss had to produce a word that fell in the space defined by the noun and the restricting adjective or letter. RT was fastest when trials were blocked and when a letter followed the presentation of the noun. This finding suggested the existence of two retrieval plans that can be executed when S has knowledge of the forthcoming type of item.     

Moray vs. the rest: The effects of extended shadowing practice

The processing requirements of the shadowing response have led to criticisms of its use in selective attention experiments. The present experiment tested a single highly skilled shadower (N. Moray) using a task requiring the detection of digits embedded in dichotic lists of letters, with attention being directed to one list by use of the shadow technique. This subject was able to detect considerably more digits in both the attended and unattended messages than were groups of unskilled shadowers previously tested. Although performance to the unattended message was high, it remained below performance to the attended message.     

Approximate methods in calculating discriminant functions

Approximate methods of solving for discriminant functions have been tried on three sets of data. The principal illustration is the problem of finding a weighted sum of scores, on four psychological tests, so that men and women may be distinguished most clearly. The work starts from the complete solution, due to R. A. Fisher, where it is necessary to solve as many simultaneous equations, dependent on the standard deviations of the tests and their mutual correlations, as there are tests. It is proposed, by way of numerical simplification, that a set of equations be substituted where some one quantity replaces all the correlations. A solution is obtained where the weights to be assigned the tests are very simply expressed in terms of differences between the mean values of tests, the standard deviations of tests, and the said quantity. The difficulty remains of finding an estimate of the arbitrary constant that will give good discrimination. If an optimal solution is made a result is obtained which, in the three sets of data considered, is almost indistinguishable from that yielded by the complete solution. The calculation of this optimal common quantity is, however, itself so considerable that another estimate, previously suggested by R. W. B. Jackson, appears more profitable. This estimate is derived simply from the variability between the total scores for each subject and the variability of each test. Using this estimate, the discriminant functions can be rapidly calculated; the results compare very favorably, in the case of the data considered, with those from the complete solution.The present work was done while the writer was employed by the Ontario Department of Health.     

Eyewitness performance in different psychological types

A study of 112 subjects examined the performance on a complex memory task by various Jungian psychological types. Although differences did not emerge in terms of overall accuracy, they did emerge in terms of susceptibility to postevent information. Introverts and intuitives, alone and in combination, were found to be more prone to accept both misleading and consistent postevent information, rendering them more likely to be inaccurate in the first case and more likely to be accurate in the second case. A variety of explanations are considered.     

Johannes Kepler’s computer simulation of the universe: Some remarks about theory in psychology

Computer simulation may be an overly seductive way of formulating theory in the social sciences. The capability of constructing complex computer simulation models may remove some of the incentive for finding simple laws. This point is illustrated via a fantasy in which the sixteenth century astronomical theorist, Johannes Kepler, uses Ms computer instead of his mind to account for extant data on stellar and planetary motion. Similarities between sixteenth century cosmology and twentieth century psychology are discussed.